By way of example, an electronic package comprises miniature electrical circuit components interconnected by and mounted on a metal lead frame. The lead frame has projecting multiple terminals, called leads. The circuit components are imbedded in encapsulant. The leads project from the encapsulant and provide connections for electrical inputs and outputs to the circuit components in the package.
A socket assembly for an electronic package allows pluggable connection of the leads of the package with circuits of a printed circuit board. A typical socket assembly includes an insulation base carrying electrical receptacle contacts that are connected with respective circuits of a printed circuit board. The leads of the electronic package are pluggably inserted into the receptacle contacts and are readily withdrawn to remove the electronic package from the socket assembly. The receptacle contacts often are damaged when the leads of the package are inserted, especially if the terminals are misaligned slightly with the receptacle contacts and the misaligned leads are forced into the receptacle contacts.
There is known in U.S. Pat. No. 3,763,459 a low insertion force socket into which misaligned leads are inserted without damaging the receptacle contacts of the socket. This advantage is achieved by having the receptacle contacts open during insertion of the misaligned leads. A reciprocating shutter mechanism is operated to close the receptacle contacts onto the leads and establish electrical connections therewith. The shutter mechanism also allows opening of the receptacle contacts to permit withdrawal of the leads. In this known socket the receptacle contacts must be received into respective apertures of the shutter mechanism. Assembly of the shutter mechanism apertures over the receptacle contacts is difficult especially if the socket is of miniature size. Another problem to overcome is the need for reducing the number of component parts required in the assembly.
The present invention is a low insertion force socket assembly having parts few in number and of minimum complexity, comprising a base, contact receiving cavities in the base along sides of the base, an electrical contact in each of the cavities, each of the contacts having a pair of opposed fingers spaced apart for receiving therebetween an electrical terminal, and the fingers of each of the contacts engage opposite sides of a respective terminal upon resilient deflection of one resilient finger of each contact toward the other finger of the contact, characterized in that; a pair of elongated rails are mounted on the base alongside the resilient fingers of respective contacts, each rail has an elongated sinuous follower surface, a cover overlies the rails, a cam on the cover is interposed between the rails, the cam has sinuous edges facing the sinuous follower surfaces of the rails, and upon reciprocation of the cam together with the cover, the sinuous edges of the cam slidably traverse against the sinuous follower surfaces of the rails, and the rails engage and resiliently reflect the resilient fingers of the contacts toward the opposed fingers.
The present invention is further characterized in that, the base includes an elongated slot, the cover includes a resilient projecting finger in detented engagement with each of the recesses, alternately in turn, upon reciprocation of the cam together with the cover.
The present invention is further characterized in that, the cover and the cam are of one piece molded dielectric construction, the latch and the finger are cantilever beams joined integrally with the cover.
The present invention is further characterized in that the base and the rails and the cover have pilot holes therein which align with one another as an indicator of correct assembly of the base, the rails, and the cover.
An object of the present invention is to provide a low insertion force socket assembly for electrical leads of an electronic package in which the assembly comprises a base, electrical receptacle contacts, a pair of rails, and a cover combined with a cam, latches and a detent mechanism.